<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        .nav {
            width: 720px;
            height: 40px;
            margin: 10px auto;
            border: 1px solid red;
            background: green;
        }

        .nav ul {
            list-style: none;
            margin: 0px;
            padding: 0px;
        }

        .nav ul li {
            float: left;
        }

        .nav ul  li a {
            display: block;
            line-height: 40px;
            width: 90px;
            text-align: center;
            text-decoration: none;
            color: white;
        }

        li a:hover {
            background: #1eff00;
        }
    </style>
</head>
<body>
<div class="nav">
    <ul>
        <li><a href="#">网站栏目</a></li>
        <li><a href="#">网站栏目</a></li>
        <li><a href="#">网站栏目</a></li>
        <li><a href="#">网站栏目</a></li>
        <li><a href="#">网站栏目</a></li>
        <li><a href="#">网站栏目</a></li>
        <li><a href="#">网站栏目</a></li>
        <li><a href="#">网站栏目</a></li>
    </ul>
</div>
</body>
</html>